The proposed K01 award will provide a 5-year training program to enable the candidate to become an independent researcher in the field of child maltreatment etiology and prevention. The primary focus is to relate biobehavioral patterns of parent-child coregulation in high-risk families to individual differences in the antecedents and outcomes associated with child maltreatment. Specific aims are to: (a) examine whether parent-child coregulation of physiology, affect, and behavior buffers families at risk for maltreatment from poor parenting, child self-regulation problems, and maltreatment incidence; and (b) examine how parent-child coregulation in response to experimental challenge and repair conditions relates to profiles of healthy, abusive, and neglectful parenting behaviors. Long-term objectives include using these findings to inform the enhanced tailoring of child maltreatment prevention approaches according to parent-child profiles of biobehavioral coregulation. Study methods will involve a longitudinal design with observational and/or questionnaire assessments at child ages 2.5, 3, and 4 years old, which will allow for the study of both dynamic micro-level patterns in response to experimental conditions in the laboratory and the modeling of macro-level developmental trajectories of child maltreatment risk across early childhood. The candidate will conduct training with Drs. Manfred Diehl and Pamela Cole, experts in self-regulation and coregulation across the lifespan from normative and developmental psychopathology perspectives; Dr David Olds, an expert in early preventive interventions with high-risk families that have been shown to prevent child maltreatment; and Drs. Kristin Buss and Elizabeth Skowron, who will offer hands-on laboratory expertise in the assessment and analysis of physiological regulation and coregulation in maltreated parent-child dyads, respectively. Drs. Steven Boker and Ruth Feldman will act as statistical consultants in dynamic time series analytic methods. Training goals are to: (1) develop skill in the use, analysis, and interpretation of physiological data; (2) develop skill in dynamic time series statistical methods with which to analyze multiple, concurrent real-time data streams within and across interaction partners; (3) enhance expertise in observational research with populations at risk for child maltreatment and the implications of basic research for child maltreatment prevention; and (4) continue professional development through scientific publications and presentations, grant writing, and training in the responsible conduct of research. The activities proposed for this award will provide a firm foundation for investigating how individual differences in dyadic biobehavioral coregulation act as markers of child maltreatment risk and therefore reduce heterogeneity in our understanding of child maltreatment etiology. This work will provide an unprecedented level of detail in early risk factors for child maltreatment, which will offer prevention scientists and practitioners more specific targets with which to better tailor existing maltreatment prevention programs.